The present invention concerns the hydrometallurgical treatment of metallurgical dust, by leaching, with a view toward separation and recovery of the useful elements contained therein, namely zinc, lead or iron.
The hydrometallurgical treatment of metallurgical dust and, more particularly dust from iron working, by leaching--generally with sulfuric acid--has until now met with two types of difficulties.
The first is that the placing in solution of a part of the iron leads to an increased consumption of the acid, and yields, after solid-liquid separation, a filtrate where the zinc, in the presence of the more electronegative iron, presents problems of electrolytical recovery. The second is due to the fact that the lead sulfate during the acid attack is insoluble and for this reason is found in the solid load mixed with iron, after solid-liquid separation and then poses a problem of reemployment, notably in iron working.